fpu: Add conversions between bfloat16 and [u]int8

[PATCH] fpu: Add conversions between bfloat16 and [u]int8

Posted by LIU Zhiwei 11 months ago

We missed these functions when upstreaming the bfloat16 support.

Signed-off-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
---
 fpu/softfloat.c         | 58 +++++++++++++++++++++++++++++++++++++++++
 include/fpu/softfloat.h | 12 +++++++++
 2 files changed, 70 insertions(+)

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 108f9cb224..576b026f4e 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -3113,6 +3113,15 @@ int64_t float64_to_int64_scalbn(float64 a, FloatRoundMode rmode, int scale,
     return parts_float_to_sint(&p, rmode, scale, INT64_MIN, INT64_MAX, s);
 }
 
+int8_t bfloat16_to_int8_scalbn(bfloat16 a, FloatRoundMode rmode, int scale,
+                               float_status *s)
+{
+    FloatParts64 p;
+
+    bfloat16_unpack_canonical(&p, a, s);
+    return parts_float_to_sint(&p, rmode, scale, INT8_MIN, INT8_MAX, s);
+}
+
 int16_t bfloat16_to_int16_scalbn(bfloat16 a, FloatRoundMode rmode, int scale,
                                  float_status *s)
 {
@@ -3379,6 +3388,11 @@ int64_t floatx80_to_int64_round_to_zero(floatx80 a, float_status *s)
     return floatx80_to_int64_scalbn(a, float_round_to_zero, 0, s);
 }
 
+int8_t bfloat16_to_int8(bfloat16 a, float_status *s)
+{
+    return bfloat16_to_int8_scalbn(a, s->float_rounding_mode, 0, s);
+}
+
 int16_t bfloat16_to_int16(bfloat16 a, float_status *s)
 {
     return bfloat16_to_int16_scalbn(a, s->float_rounding_mode, 0, s);
@@ -3394,6 +3408,11 @@ int64_t bfloat16_to_int64(bfloat16 a, float_status *s)
     return bfloat16_to_int64_scalbn(a, s->float_rounding_mode, 0, s);
 }
 
+int8_t bfloat16_to_int8_round_to_zero(bfloat16 a, float_status *s)
+{
+    return bfloat16_to_int8_scalbn(a, float_round_to_zero, 0, s);
+}
+
 int16_t bfloat16_to_int16_round_to_zero(bfloat16 a, float_status *s)
 {
     return bfloat16_to_int16_scalbn(a, float_round_to_zero, 0, s);
@@ -3503,6 +3522,15 @@ uint64_t float64_to_uint64_scalbn(float64 a, FloatRoundMode rmode, int scale,
     return parts_float_to_uint(&p, rmode, scale, UINT64_MAX, s);
 }
 
+uint8_t bfloat16_to_uint8_scalbn(bfloat16 a, FloatRoundMode rmode,
+                                 int scale, float_status *s)
+{
+    FloatParts64 p;
+
+    bfloat16_unpack_canonical(&p, a, s);
+    return parts_float_to_uint(&p, rmode, scale, UINT8_MAX, s);
+}
+
 uint16_t bfloat16_to_uint16_scalbn(bfloat16 a, FloatRoundMode rmode,
                                    int scale, float_status *s)
 {
@@ -3728,6 +3756,11 @@ Int128 float128_to_uint128_round_to_zero(float128 a, float_status *s)
     return float128_to_uint128_scalbn(a, float_round_to_zero, 0, s);
 }
 
+uint8_t bfloat16_to_uint8(bfloat16 a, float_status *s)
+{
+    return bfloat16_to_uint8_scalbn(a, s->float_rounding_mode, 0, s);
+}
+
 uint16_t bfloat16_to_uint16(bfloat16 a, float_status *s)
 {
     return bfloat16_to_uint16_scalbn(a, s->float_rounding_mode, 0, s);
@@ -3743,6 +3776,11 @@ uint64_t bfloat16_to_uint64(bfloat16 a, float_status *s)
     return bfloat16_to_uint64_scalbn(a, s->float_rounding_mode, 0, s);
 }
 
+uint8_t bfloat16_to_uint8_round_to_zero(bfloat16 a, float_status *s)
+{
+    return bfloat16_to_uint8_scalbn(a, float_round_to_zero, 0, s);
+}
+
 uint16_t bfloat16_to_uint16_round_to_zero(bfloat16 a, float_status *s)
 {
     return bfloat16_to_uint16_scalbn(a, float_round_to_zero, 0, s);
@@ -3898,6 +3936,11 @@ bfloat16 int16_to_bfloat16_scalbn(int16_t a, int scale, float_status *status)
     return int64_to_bfloat16_scalbn(a, scale, status);
 }
 
+bfloat16 int8_to_bfloat16_scalbn(int8_t a, int scale, float_status *status)
+{
+    return int64_to_bfloat16_scalbn(a, scale, status);
+}
+
 bfloat16 int64_to_bfloat16(int64_t a, float_status *status)
 {
     return int64_to_bfloat16_scalbn(a, 0, status);
@@ -3913,6 +3956,11 @@ bfloat16 int16_to_bfloat16(int16_t a, float_status *status)
     return int64_to_bfloat16_scalbn(a, 0, status);
 }
 
+bfloat16 int8_to_bfloat16(int8_t a, float_status *status)
+{
+    return int64_to_bfloat16_scalbn(a, 0, status);
+}
+
 float128 int128_to_float128(Int128 a, float_status *status)
 {
     FloatParts128 p = { };
@@ -4108,6 +4156,11 @@ bfloat16 uint16_to_bfloat16_scalbn(uint16_t a, int scale, float_status *status)
     return uint64_to_bfloat16_scalbn(a, scale, status);
 }
 
+bfloat16 uint8_to_bfloat16_scalbn(uint8_t a, int scale, float_status *status)
+{
+    return uint64_to_bfloat16_scalbn(a, scale, status);
+}
+
 bfloat16 uint64_to_bfloat16(uint64_t a, float_status *status)
 {
     return uint64_to_bfloat16_scalbn(a, 0, status);
@@ -4123,6 +4176,11 @@ bfloat16 uint16_to_bfloat16(uint16_t a, float_status *status)
     return uint64_to_bfloat16_scalbn(a, 0, status);
 }
 
+bfloat16 uint8_to_bfloat16(uint8_t a, float_status *status)
+{
+    return uint64_to_bfloat16_scalbn(a, 0, status);
+}
+
 float128 uint64_to_float128(uint64_t a, float_status *status)
 {
     FloatParts128 p;
diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
index 3dcf20e3a2..6d02f619d0 100644
--- a/include/fpu/softfloat.h
+++ b/include/fpu/softfloat.h
@@ -366,6 +366,8 @@ float32 bfloat16_to_float32(bfloat16, float_status *status);
 bfloat16 float64_to_bfloat16(float64 a, float_status *status);
 float64 bfloat16_to_float64(bfloat16 a, float_status *status);
 
+int8_t bfloat16_to_int8_scalbn(bfloat16, FloatRoundMode,
+                               int, float_status *status);
 int16_t bfloat16_to_int16_scalbn(bfloat16, FloatRoundMode,
                                  int, float_status *status);
 int32_t bfloat16_to_int32_scalbn(bfloat16, FloatRoundMode,
@@ -373,14 +375,18 @@ int32_t bfloat16_to_int32_scalbn(bfloat16, FloatRoundMode,
 int64_t bfloat16_to_int64_scalbn(bfloat16, FloatRoundMode,
                                  int, float_status *status);
 
+int8_t bfloat16_to_int8(bfloat16, float_status *status);
 int16_t bfloat16_to_int16(bfloat16, float_status *status);
 int32_t bfloat16_to_int32(bfloat16, float_status *status);
 int64_t bfloat16_to_int64(bfloat16, float_status *status);
 
+int8_t bfloat16_to_int8_round_to_zero(bfloat16, float_status *status);
 int16_t bfloat16_to_int16_round_to_zero(bfloat16, float_status *status);
 int32_t bfloat16_to_int32_round_to_zero(bfloat16, float_status *status);
 int64_t bfloat16_to_int64_round_to_zero(bfloat16, float_status *status);
 
+uint8_t bfloat16_to_uint8_scalbn(bfloat16 a, FloatRoundMode,
+                                 int, float_status *status);
 uint16_t bfloat16_to_uint16_scalbn(bfloat16 a, FloatRoundMode,
                                    int, float_status *status);
 uint32_t bfloat16_to_uint32_scalbn(bfloat16 a, FloatRoundMode,
@@ -388,24 +394,30 @@ uint32_t bfloat16_to_uint32_scalbn(bfloat16 a, FloatRoundMode,
 uint64_t bfloat16_to_uint64_scalbn(bfloat16 a, FloatRoundMode,
                                    int, float_status *status);
 
+uint8_t bfloat16_to_uint8(bfloat16 a, float_status *status);
 uint16_t bfloat16_to_uint16(bfloat16 a, float_status *status);
 uint32_t bfloat16_to_uint32(bfloat16 a, float_status *status);
 uint64_t bfloat16_to_uint64(bfloat16 a, float_status *status);
 
+uint8_t bfloat16_to_uint8_round_to_zero(bfloat16 a, float_status *status);
 uint16_t bfloat16_to_uint16_round_to_zero(bfloat16 a, float_status *status);
 uint32_t bfloat16_to_uint32_round_to_zero(bfloat16 a, float_status *status);
 uint64_t bfloat16_to_uint64_round_to_zero(bfloat16 a, float_status *status);
 
+bfloat16 int8_to_bfloat16_scalbn(int8_t a, int, float_status *status);
 bfloat16 int16_to_bfloat16_scalbn(int16_t a, int, float_status *status);
 bfloat16 int32_to_bfloat16_scalbn(int32_t a, int, float_status *status);
 bfloat16 int64_to_bfloat16_scalbn(int64_t a, int, float_status *status);
+bfloat16 uint8_to_bfloat16_scalbn(uint8_t a, int, float_status *status);
 bfloat16 uint16_to_bfloat16_scalbn(uint16_t a, int, float_status *status);
 bfloat16 uint32_to_bfloat16_scalbn(uint32_t a, int, float_status *status);
 bfloat16 uint64_to_bfloat16_scalbn(uint64_t a, int, float_status *status);
 
+bfloat16 int8_to_bfloat16(int8_t a, float_status *status);
 bfloat16 int16_to_bfloat16(int16_t a, float_status *status);
 bfloat16 int32_to_bfloat16(int32_t a, float_status *status);
 bfloat16 int64_to_bfloat16(int64_t a, float_status *status);
+bfloat16 uint8_to_bfloat16(uint8_t a, float_status *status);
 bfloat16 uint16_to_bfloat16(uint16_t a, float_status *status);
 bfloat16 uint32_to_bfloat16(uint32_t a, float_status *status);
 bfloat16 uint64_to_bfloat16(uint64_t a, float_status *status);
-- 
2.17.1

Re: [PATCH] fpu: Add conversions between bfloat16 and [u]int8

Posted by LIU Zhiwei 7 months, 2 weeks ago

Hi Richard,

Can you pick it to your tree?

Thanks,
Zhiwei

On 2023/5/31 14:54, LIU Zhiwei wrote:
> We missed these functions when upstreaming the bfloat16 support.
>
> Signed-off-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
> ---
>   fpu/softfloat.c         | 58 +++++++++++++++++++++++++++++++++++++++++
>   include/fpu/softfloat.h | 12 +++++++++
>   2 files changed, 70 insertions(+)
>
> diff --git a/fpu/softfloat.c b/fpu/softfloat.c
> index 108f9cb224..576b026f4e 100644
> --- a/fpu/softfloat.c
> +++ b/fpu/softfloat.c
> @@ -3113,6 +3113,15 @@ int64_t float64_to_int64_scalbn(float64 a, FloatRoundMode rmode, int scale,
>       return parts_float_to_sint(&p, rmode, scale, INT64_MIN, INT64_MAX, s);
>   }
>   
> +int8_t bfloat16_to_int8_scalbn(bfloat16 a, FloatRoundMode rmode, int scale,
> +                               float_status *s)
> +{
> +    FloatParts64 p;
> +
> +    bfloat16_unpack_canonical(&p, a, s);
> +    return parts_float_to_sint(&p, rmode, scale, INT8_MIN, INT8_MAX, s);
> +}
> +
>   int16_t bfloat16_to_int16_scalbn(bfloat16 a, FloatRoundMode rmode, int scale,
>                                    float_status *s)
>   {
> @@ -3379,6 +3388,11 @@ int64_t floatx80_to_int64_round_to_zero(floatx80 a, float_status *s)
>       return floatx80_to_int64_scalbn(a, float_round_to_zero, 0, s);
>   }
>   
> +int8_t bfloat16_to_int8(bfloat16 a, float_status *s)
> +{
> +    return bfloat16_to_int8_scalbn(a, s->float_rounding_mode, 0, s);
> +}
> +
>   int16_t bfloat16_to_int16(bfloat16 a, float_status *s)
>   {
>       return bfloat16_to_int16_scalbn(a, s->float_rounding_mode, 0, s);
> @@ -3394,6 +3408,11 @@ int64_t bfloat16_to_int64(bfloat16 a, float_status *s)
>       return bfloat16_to_int64_scalbn(a, s->float_rounding_mode, 0, s);
>   }
>   
> +int8_t bfloat16_to_int8_round_to_zero(bfloat16 a, float_status *s)
> +{
> +    return bfloat16_to_int8_scalbn(a, float_round_to_zero, 0, s);
> +}
> +
>   int16_t bfloat16_to_int16_round_to_zero(bfloat16 a, float_status *s)
>   {
>       return bfloat16_to_int16_scalbn(a, float_round_to_zero, 0, s);
> @@ -3503,6 +3522,15 @@ uint64_t float64_to_uint64_scalbn(float64 a, FloatRoundMode rmode, int scale,
>       return parts_float_to_uint(&p, rmode, scale, UINT64_MAX, s);
>   }
>   
> +uint8_t bfloat16_to_uint8_scalbn(bfloat16 a, FloatRoundMode rmode,
> +                                 int scale, float_status *s)
> +{
> +    FloatParts64 p;
> +
> +    bfloat16_unpack_canonical(&p, a, s);
> +    return parts_float_to_uint(&p, rmode, scale, UINT8_MAX, s);
> +}
> +
>   uint16_t bfloat16_to_uint16_scalbn(bfloat16 a, FloatRoundMode rmode,
>                                      int scale, float_status *s)
>   {
> @@ -3728,6 +3756,11 @@ Int128 float128_to_uint128_round_to_zero(float128 a, float_status *s)
>       return float128_to_uint128_scalbn(a, float_round_to_zero, 0, s);
>   }
>   
> +uint8_t bfloat16_to_uint8(bfloat16 a, float_status *s)
> +{
> +    return bfloat16_to_uint8_scalbn(a, s->float_rounding_mode, 0, s);
> +}
> +
>   uint16_t bfloat16_to_uint16(bfloat16 a, float_status *s)
>   {
>       return bfloat16_to_uint16_scalbn(a, s->float_rounding_mode, 0, s);
> @@ -3743,6 +3776,11 @@ uint64_t bfloat16_to_uint64(bfloat16 a, float_status *s)
>       return bfloat16_to_uint64_scalbn(a, s->float_rounding_mode, 0, s);
>   }
>   
> +uint8_t bfloat16_to_uint8_round_to_zero(bfloat16 a, float_status *s)
> +{
> +    return bfloat16_to_uint8_scalbn(a, float_round_to_zero, 0, s);
> +}
> +
>   uint16_t bfloat16_to_uint16_round_to_zero(bfloat16 a, float_status *s)
>   {
>       return bfloat16_to_uint16_scalbn(a, float_round_to_zero, 0, s);
> @@ -3898,6 +3936,11 @@ bfloat16 int16_to_bfloat16_scalbn(int16_t a, int scale, float_status *status)
>       return int64_to_bfloat16_scalbn(a, scale, status);
>   }
>   
> +bfloat16 int8_to_bfloat16_scalbn(int8_t a, int scale, float_status *status)
> +{
> +    return int64_to_bfloat16_scalbn(a, scale, status);
> +}
> +
>   bfloat16 int64_to_bfloat16(int64_t a, float_status *status)
>   {
>       return int64_to_bfloat16_scalbn(a, 0, status);
> @@ -3913,6 +3956,11 @@ bfloat16 int16_to_bfloat16(int16_t a, float_status *status)
>       return int64_to_bfloat16_scalbn(a, 0, status);
>   }
>   
> +bfloat16 int8_to_bfloat16(int8_t a, float_status *status)
> +{
> +    return int64_to_bfloat16_scalbn(a, 0, status);
> +}
> +
>   float128 int128_to_float128(Int128 a, float_status *status)
>   {
>       FloatParts128 p = { };
> @@ -4108,6 +4156,11 @@ bfloat16 uint16_to_bfloat16_scalbn(uint16_t a, int scale, float_status *status)
>       return uint64_to_bfloat16_scalbn(a, scale, status);
>   }
>   
> +bfloat16 uint8_to_bfloat16_scalbn(uint8_t a, int scale, float_status *status)
> +{
> +    return uint64_to_bfloat16_scalbn(a, scale, status);
> +}
> +
>   bfloat16 uint64_to_bfloat16(uint64_t a, float_status *status)
>   {
>       return uint64_to_bfloat16_scalbn(a, 0, status);
> @@ -4123,6 +4176,11 @@ bfloat16 uint16_to_bfloat16(uint16_t a, float_status *status)
>       return uint64_to_bfloat16_scalbn(a, 0, status);
>   }
>   
> +bfloat16 uint8_to_bfloat16(uint8_t a, float_status *status)
> +{
> +    return uint64_to_bfloat16_scalbn(a, 0, status);
> +}
> +
>   float128 uint64_to_float128(uint64_t a, float_status *status)
>   {
>       FloatParts128 p;
> diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
> index 3dcf20e3a2..6d02f619d0 100644
> --- a/include/fpu/softfloat.h
> +++ b/include/fpu/softfloat.h
> @@ -366,6 +366,8 @@ float32 bfloat16_to_float32(bfloat16, float_status *status);
>   bfloat16 float64_to_bfloat16(float64 a, float_status *status);
>   float64 bfloat16_to_float64(bfloat16 a, float_status *status);
>   
> +int8_t bfloat16_to_int8_scalbn(bfloat16, FloatRoundMode,
> +                               int, float_status *status);
>   int16_t bfloat16_to_int16_scalbn(bfloat16, FloatRoundMode,
>                                    int, float_status *status);
>   int32_t bfloat16_to_int32_scalbn(bfloat16, FloatRoundMode,
> @@ -373,14 +375,18 @@ int32_t bfloat16_to_int32_scalbn(bfloat16, FloatRoundMode,
>   int64_t bfloat16_to_int64_scalbn(bfloat16, FloatRoundMode,
>                                    int, float_status *status);
>   
> +int8_t bfloat16_to_int8(bfloat16, float_status *status);
>   int16_t bfloat16_to_int16(bfloat16, float_status *status);
>   int32_t bfloat16_to_int32(bfloat16, float_status *status);
>   int64_t bfloat16_to_int64(bfloat16, float_status *status);
>   
> +int8_t bfloat16_to_int8_round_to_zero(bfloat16, float_status *status);
>   int16_t bfloat16_to_int16_round_to_zero(bfloat16, float_status *status);
>   int32_t bfloat16_to_int32_round_to_zero(bfloat16, float_status *status);
>   int64_t bfloat16_to_int64_round_to_zero(bfloat16, float_status *status);
>   
> +uint8_t bfloat16_to_uint8_scalbn(bfloat16 a, FloatRoundMode,
> +                                 int, float_status *status);
>   uint16_t bfloat16_to_uint16_scalbn(bfloat16 a, FloatRoundMode,
>                                      int, float_status *status);
>   uint32_t bfloat16_to_uint32_scalbn(bfloat16 a, FloatRoundMode,
> @@ -388,24 +394,30 @@ uint32_t bfloat16_to_uint32_scalbn(bfloat16 a, FloatRoundMode,
>   uint64_t bfloat16_to_uint64_scalbn(bfloat16 a, FloatRoundMode,
>                                      int, float_status *status);
>   
> +uint8_t bfloat16_to_uint8(bfloat16 a, float_status *status);
>   uint16_t bfloat16_to_uint16(bfloat16 a, float_status *status);
>   uint32_t bfloat16_to_uint32(bfloat16 a, float_status *status);
>   uint64_t bfloat16_to_uint64(bfloat16 a, float_status *status);
>   
> +uint8_t bfloat16_to_uint8_round_to_zero(bfloat16 a, float_status *status);
>   uint16_t bfloat16_to_uint16_round_to_zero(bfloat16 a, float_status *status);
>   uint32_t bfloat16_to_uint32_round_to_zero(bfloat16 a, float_status *status);
>   uint64_t bfloat16_to_uint64_round_to_zero(bfloat16 a, float_status *status);
>   
> +bfloat16 int8_to_bfloat16_scalbn(int8_t a, int, float_status *status);
>   bfloat16 int16_to_bfloat16_scalbn(int16_t a, int, float_status *status);
>   bfloat16 int32_to_bfloat16_scalbn(int32_t a, int, float_status *status);
>   bfloat16 int64_to_bfloat16_scalbn(int64_t a, int, float_status *status);
> +bfloat16 uint8_to_bfloat16_scalbn(uint8_t a, int, float_status *status);
>   bfloat16 uint16_to_bfloat16_scalbn(uint16_t a, int, float_status *status);
>   bfloat16 uint32_to_bfloat16_scalbn(uint32_t a, int, float_status *status);
>   bfloat16 uint64_to_bfloat16_scalbn(uint64_t a, int, float_status *status);
>   
> +bfloat16 int8_to_bfloat16(int8_t a, float_status *status);
>   bfloat16 int16_to_bfloat16(int16_t a, float_status *status);
>   bfloat16 int32_to_bfloat16(int32_t a, float_status *status);
>   bfloat16 int64_to_bfloat16(int64_t a, float_status *status);
> +bfloat16 uint8_to_bfloat16(uint8_t a, float_status *status);
>   bfloat16 uint16_to_bfloat16(uint16_t a, float_status *status);
>   bfloat16 uint32_to_bfloat16(uint32_t a, float_status *status);
>   bfloat16 uint64_to_bfloat16(uint64_t a, float_status *status);

Re: [PATCH] fpu: Add conversions between bfloat16 and [u]int8

Posted by Richard Henderson 7 months, 1 week ago

On 9/13/23 02:54, LIU Zhiwei wrote:
> Hi Richard,
> 
> Can you pick it to your tree?

Sure. Queued to tcg-next.


r~

Re: [PATCH] fpu: Add conversions between bfloat16 and [u]int8

Posted by Richard Henderson 11 months ago

On 5/30/23 23:54, LIU Zhiwei wrote:
> We missed these functions when upstreaming the bfloat16 support.
> 
> Signed-off-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>

They look ok, so far as it goes.  What will they be used for?


r~

Re: [PATCH] fpu: Add conversions between bfloat16 and [u]int8

Posted by LIU Zhiwei 11 months ago

On 2023/6/1 1:47, Richard Henderson wrote:
> On 5/30/23 23:54, LIU Zhiwei wrote:
>> We missed these functions when upstreaming the bfloat16 support.
>>
>> Signed-off-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
>
> They look ok, so far as it goes.  What will they be used for?

T-Head Xuantie CPUs custom extension need these interfaces. It uses a 
custom CSR(still not upstream) to switch between the fp16 and bfloat16. 
All fp16 instructions(Zfh) can process the bfloat16 types. In its custom 
matrix extension[1] or vector extension, this feature is also supported.

As a side note, the RISC-V port support for custom extension at least 
should have these aspects:

  *   ISA decoding (Ready, Philipp Tomsich)
  *   CSR (WIP, Andes?)
  *   Disassemble(Under review, Christopher)
  * Errata(Not start)
  * Split TB flags like ARM for custom(In the wild for the Xuantie CPUs)

1. 
https://github.com/T-head-Semi/riscv-matrix-extension-spec/releases/tag/v0.1.0

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